Subject: linux-next: build failure after merge of the mm-hotfixes tree

From: Stephen Rothwell <[email-masked]>
Date: Mon, 8 Dec 2025 08:35:11 +1100

Hi all,

After merging the mm-hotfixes tree, today's linux-next build (x86_64
allmodconfig) failed like this:

In file included from arch/x86/include/asm/bug.h:193,
                 from include/linux/bug.h:5,
                 from include/linux/kasan.h:5,
                 from mm/kasan/common.c:14:
mm/kasan/common.c: In function '__kasan_unpoison_vmap_areas':
mm/kasan/common.c:594:34: error: 'KASAN_VMALLOC_KEEP_TAG' undeclared (first use in this function); did you mean 'KASAN_VMALLOC_PAGE_RANGE'?
  594 |         if (WARN_ON_ONCE(flags & KASAN_VMALLOC_KEEP_TAG))
      |                                  ^~~~~~~~~~~~~~~~~~~~~~
include/asm-generic/bug.h:120:32: note: in definition of macro 'WARN_ON_ONCE'
  120 |         int __ret_warn_on = !!(condition);                              \
      |                                ^~~~~~~~~
mm/kasan/common.c:594:34: note: each undeclared identifier is reported only once for each function it appears in
  594 |         if (WARN_ON_ONCE(flags & KASAN_VMALLOC_KEEP_TAG))
      |                                  ^~~~~~~~~~~~~~~~~~~~~~
include/asm-generic/bug.h:120:32: note: in definition of macro 'WARN_ON_ONCE'
  120 |         int __ret_warn_on = !!(condition);                              \
      |                                ^~~~~~~~~

Caused by commit

  6b83afdcfa93 ("kasan: unpoison vms[area] addresses with a common tag")

I have reverted that commit (and the following 2 fixes) for today.

-- 
Cheers,
Stephen Rothwell